1. Field of the Invention
Embodiments of the present invention generally relate to methods for the removal of copper oxides during semiconductor fabrication.
2. Description of the Related Art
The dielectric constant (k) of interlayer dielectric (ILD) films is continually decreasing as device scaling continues. Minimizing integration damage on low dielectric constant (low-k) films is important to be able to continue decreasing feature sizes. However, as feature sizes shrink, improvement in the resistive capacitance and reliability of ILD films becomes a serious challenge.
Current techniques for the removal of copper oxides (CuO) and chemical mechanical planarization (CMP) residues involve the use of ammonia (NH3) or hydrogen (H2) plasmas. Removal of the copper oxides and CMP residues are necessary to improve the electromigration (EM) of the metallization structures and the time dependent dielectric breakdown (TDDB) of the ILD films. Also, leftover copper oxides and CMP residues can reduce adhesion to subsequently formed layers. However, exposing low-k films to NH3 and H2 plasmas modifies the ILD film and increases the k value.
Thus, a new method for the removal of copper oxides and CMP residues is necessary to minimize the k value increase of low-k films.